• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.387-393
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• 1997

In order to apply WO3 thin films to the semiconducting NOx gas sensors as a sensing material, which have been expected to show good electrical properties, such as large sensitivity, rapid responsibility, and high selectivity, the fabrication method and their sensing characteristics were studied. The variations of surface morphologies, crystallographic orientations and crystallinity with the WO3 thin film growing methods thermal evaporation and DC sputtering methods were investigated by using scanning electron microscopy (SEM) and X-ray diffraction(XRD) analysis. As a result of sensitivity (Rgas/Rair) measurements for the 5 ppm NO2 test gas, the sensitivity values were 113 for the sputtered films and 93 for the evaporated films. It was also observed that the recovery rate of a sensing signal after measuring sensitivity was faster in the sputtered films than in the evaporated films.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.37-45
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• 2014

Korean wh-questions and yes-no questions have morphologically the same structure. In speech, however, two types of questions are distinguished by prosodic difference. In this study, we examined if Korean native speakers can distinguish wh-question and yes-no questions produced by Chinese Korean leaners based on the prosodic information contained in the sentences. For this purpose, we performed perception analysis, and 15 Korean native speakers participated in the perception test. The results show that two types of interrogative sentences produced by Chinese Korean leaners were not distinguished by constant pitch contours. These results reveal that Chinese Korean leaners cannot match prosodic meaning and prosodic form. The most saliant prosodic feature used perceptually by native speakers to discriminate two types of interrogative sentences is pitch difference between the F0 pick of wh-word and boundary tone.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.250-253
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• 2009

This paper presents NR (No Reference) Quality assessment method for IPTV or mobile IPTV. Because No Reference quality assessment method does not access the original signal so it is suitable for the real-time streaming service. Our proposed method use decoding parameters, such as quantization parameter, motion vector, and packet loss as a major network parameter. To evaluate performance of the proposed algorithm, we carried out subjective test of video quality with the ITU-T P.910 ACR (Absolute Category Rating) method and obtained the mean opinion score (MOS) value for QVGA 180 video sequence coded by H.264/AVC encoder. Experimental results show the proposed quality metric has a high correlation (84%) to subjective quality.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.625-631
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• 1993

The types of the products of the reactions between RuH(NO)(Cyttp) and alkynes are sensitive to the nature of alkynes. Terminal, nonactivated alkynes (HC${\equiv}$CR, R=Ph, hexyl and $CH_2OH)$ produce acetylide complexes and terminal (HC${\equiv}$CR, R=C(O)Me, COOEt) or internal activated ones (RC${\equiv}$ CR, R=COOMe) lead to form alkenyl complexes. On the other hand, internal nonactivated alkynes (RC${\equiv}$CR, R=Ph) do not show reactivity toward RuH(NO)(Cyttp). These products can be rationalized by the cis-concerted mechanism but the radical pathway appears to work in the reaction of propargyl chloride. From the spectroscopic data, the trigonal bipyramidal structure with a linear NO group is proposed for these products.

• ETRI Journal
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• v.43 no.3
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• pp.538-548
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• 2021

This paper proposes an approach to improve the performance of no-reference video quality assessment for sports videos with dynamic motion scenes using an efficient spatiotemporal model. In the proposed method, we divide the video sequences into video blocks and apply a 3D shearlet transform that can efficiently extract primary spatiotemporal features to capture dynamic natural motion scene statistics from the incoming video blocks. The concatenation of a deep residual bidirectional gated recurrent neural network and logistic regression is used to learn the spatiotemporal correlation more robustly and predict the perceptual quality score. In addition, conditional video block-wise constraints are incorporated into the objective function to improve quality estimation performance for the entire video. The experimental results show that the proposed method extracts spatiotemporal motion information more effectively and predicts the video quality with higher accuracy than the conventional no-reference video quality assessment methods.

• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.149-165
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• 1996

In order to get some basic datas on environmental friendly funtion against soil and water pollution and safe vegetable production by organic farming, chemical characteristics of soils cultivated by the conventional farming, greengouse cultivation and organic farming and acumulation of NO3--N in chinese cabbage and lettuce were analysed. The highest value of NO3--N in 0-30cm subsoil of organic farming was found among the 3 different farming systems, and it was 3.6 and 6.6 times higher than those of conventional farming in chinese cabbage and lettuce respectively. P2O5 also show high accumulation in the rhizosphere of organic farming compared to convnetional farming. The accumulation of NO3--N and P2O5 in the rhizosphere of organic farming were simial to those of greenhouse cultivation. The NO3- accumulation in chinese cabbage and lettuce by organic farming reach 3224ppm in chinese cabbage and 2543ppm in lettuce and it were 4.7 and 6.4 times higher than those of convnetional farming. It is urgently necessary to introduce the basic standard of IFOAM, EU and FAO/WHO Codex on organic agriculture into korean organic agriculture for operation of environmental friendly system and production of safe vegetable in terms of NO3-.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.912-917
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• 2007

Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. An amperometric gas sensor usually generates sensing signal of electric current along the proportion of the concentration of target gas under the condition of limiting current. For narrow variations of gas concentration, the amperometric gas sensor can show higher precision than a potentiometric gas sensor does. In additional, cross sensitivities to interfering gases can possibly be mitigated by choosing applied voltage and electrode materials properly. In order to improve the sensitivity to $NO_2$, the device was attached with Au reference electrode to form the amperometric gas sensor device with three electrodes. With the fixed bias voltage being applied between the sensing and counter electrodes, the current between the sensing and reference electrodes was measured as a sensing signal. The response to $NO_2$ gas was obviously enhanced and suppressed with a positive bias, respectively, while the reverse current occurred with a negative bias. The way to enhance the sensitivity of $NO_2$ gas sensor was thus realized. It was shown that the response to $NO_2$ gas could be enhanced sensitivity by changing the bias voltage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5C
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• pp.361-370
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• 2008

NoC is adopted for data communication between processors and IPs in MPSoC system. NoC has an advantage of scalability in that system can be easily expanded just by adding switches. However, as the number of switches increases, chip area increases as well as data transfer latency. This paper proposes an architecture that can reduce the number of switches in the system by sharing network interfaces. To reduce NI area, the modules sharing network interface use a common buffer in network interface. Experimental results show that the chip area has been reduced by 46.5% and data transfer latency by 17.1%, respectively, compared to conventional architecture.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.142-149
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• 2012

The reduction characteristics of $NO_2$ to NO are experimentally studied over a platinum-based catalyst, especially at lower temperatures below about $200^{\circ}C$. In the present work, two types of steady-state experiments, engine bench and synthetic gas bench tests, are carried out in sequence. Steady-state engine bench tests with the DOC mounted on a light duty 4-cylinder 2.0 liter turbocharged diesel engine are performed and prove that CO plays a major role in $NO_2$ abatement at temperatures below the light-off temperature of CO oxidation, about $200^{\circ}C$. Synthetic gas bench tests are then performed using synthetic gas mixtures with CO, $C_3H_6$, NO, $NO_2$, $O_2$, $H_2O$ and $N_2$ in the $140{\sim}450^{\circ}C$ T-range and show that both CO and $C_3H_6$ are capable of reducing $NO_2$. It is noted that the reaction rate of $NO_2$ with $C_3H_6$ is much higher than that with CO. At temperatures below about $200^{\circ}C$, the reduction of $NO_2$ to NO is promoted with increasing CO concentration and $NO_2$/$NO_X$ ratio and with decreasing $O_2$ concentration, as well as with the presence of $H_2O$.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.64-71
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• 2013

In this study we designed a lean $NO_x$ trap (LNT) model with $GT-POWER^{TM}$ program and then the LNT model was compared to the bench flow reactor test results. This model consists of 9 kinetic reactions to represent the main steps of NO oxidation, $NO_x$ adsorption, $NO_x$ release and then its reduction. The comparison was performed on the operating conditions at the space velocity of 50,000 1/hr and 80,000 1/hr with the temperature range of $200^{\circ}C{\sim}500^{\circ}C$ with the even spaced temperature step of $50^{\circ}C$. The experimental results show that the $NO_x$ conversion efficiency was enhanced by the temperature up to $350^{\circ}C$ and then decayed at higher temperatures. The LNT model predicts the similar trend of the $NO_x$ conversion efficiency to the experimental results below $350^{\circ}C$, but overestimates above $350^{\circ}C$. This overestimation comes from the higher reduction efficiency which was obtained by the different reduction gas composition such as $C_3H_6$ in the model to replace $CH_4$, $C_2H_4$ in the bench test.